Exiting the market after a decline — and thus failing to participate in a cyclical rebound — is truly the cardinal sin in investing. Experiencing a mark-to-market loss in the downward phase of a cycle isn’t fatal in and of itself, as long as you hold through the beneficial upward part as well. It’s converting that downward fluctuation into a permanent loss by selling out at the bottom that’s really terrible. Thus understanding cycles and having the emotional and financial wherewithal needed to live through them is an essential ingredient in investment success. (See here)
